The final phase of the chemotactic process results in the actual movement of the cell. This movement involves a complex set of cellular processes and includes the generation of protrusive, retractive, and adhesive forces. The mechanisms underlying these forces are poorly understood, partially due to the lack of quantitative data. For example, it is unclear how Dlctyostellum cells adhere to the substrate, and how the substrate adhesiveness and rigidity affect cell motility. New experimental techniques, however, open up the possibility of examining the forces involved in cell migration and can provide quantitative data necessary for a deeper understanding of cell motility. Our goal in this project is two-fold: the first goal is to determine the forces at the substrate-cell interface and their role in cell motility using novel microfluidics techniques in combination with innovative substrates that allow for simultaneous fraction microscopy and Total Internal Reflection Fluorescence (TIRF) microscopy. The second goal is to use this experimental data to build a comprehensive computational model for cell motility that includes force generation, cell-substrate interactions, membrane properties and cell deformations. As in project 1 and 2, the experimental-computational interaction will be critical to achieving our goals. Specifically, we propose: